}is it possible that this make the black part of the texture transparent GLES10.glClearColor(0.0f, 0.0f, 0.0f, 0.f); in ARtoolkit render?I tried to change this but nothing happens.Any idea how to solve this?

By default, the texture loader creates an alpha channel out of the black pixels of a texture. If you don't want that, use the constructor that takes the boolean argument in addition and set it to true.Anyway, the alpha channel will only be taken into account when transparency is enabled on the object. Some objects are exported in a way that the loader defaults to transparency. Just try Michael's suggestion and see if that helps.

No, it can't. Clearing the framebuffer has no influence on how a texture will be rendered. It might be caused by the fact that the framebuffer itself is transparent. Try setTransparency(-1) in combination with using the new Texture(..., true)-constructor for your textures.